VI 
They are generally unequal, the two lateral pieces corresponding in 
form and size, while that between them, called the lip, is of some other 
form and size; in the genus Thelymitra, however, and inPaxtonia, they 
are all alike. Nothing can he more variable than the proportions they 
bear to each other and to the exterior pieces. It is only a few of their 
modifications which it seems important to notice. The lateral pieces 
are occasionally bifid, as in certain species of Habenaria ; in Megacli- 
niura falcatum they arc glandular at the apex ; in most cases they are 
distinct from the column, but in Lepanthes, Gongora, Disa, and some 
others, they are adnate to that organ ; in no instance are they spurred 
or saccate. The Up is either distinct from the column or united to it, 
stalked at its base or dilated there, and often extended into a bag or 
spur, which is sometimes, as in certain species of the genus Epidendrum, 
consolidated with the ovary; very rarely it has two spurs, as in Diplo- 
centrum. In the instances of Camarotis and Acropera it is saccate at the 
point. Its form is infinitely varied, the extremes of variation being 
Paxtonia for simplicity, and Coryanthes or Stanhopea for complexity; 
these and all other complicated forms may without difficulty be reduced 
to a three-lobed type, the simple form of which is found in Maxillaria, 
Bletia, and many Cattleyas. The lip is often so slightly articulated with 
the column as to swing to and fro upon the least disturbance, on which 
account it sometimes seems as if it were endowed with a power of spon¬ 
taneous motion ; this is particularly apparent in certain species of Pte- 
rostylis. There is a frequent tendency in the lip to produce tubercles or 
lamellae upon its surface, the latter are always confined to the veins, the 
former are principally found near the base of the lip, and do not appear 
to have any relation to the veins ; it is in the genus Oncidium, Eria, and 
Zy go petal um that these bodies, the use of which is unknown, are most 
conspicuous. Not unfrequently the lip is hairy, convex, and so marked 
and coloured as to bear no little resemblance to an insect. 
It is usual to call the exterior series of the floral envelopes, calyx, and 
the interior, corolla, and it is convenient so to consider them for purposes 
of description. It is however probable, both from the analogy of Ma- 
rantaceae and Zingiberaceae, and for other reasons, that the so called sepals 
arc really the petals, and that the so called petals are an outer row of 
sterile stamens. It is clear that the supposed calyx is not the most 
